At present, medium & low voltage power in China relies considerably on an overhead bare conductor (hereafter referred to as an overhead line) to transmit. But, as population density increases, the contradiction between urban buildings or thick green areas and overhead transmission lines of an urban power network is increasingly prominent. Because an uninsulated bare conductive wire is erected on a tower pole by means of a spatial distance and an insulator, many accidents often occur in both sides of an urban street, a housing district, and so on. To guarantee personal and property safety, State Grid Corporation of China now considers the need to achieve 100% overhead line insulation. For a new erected line, an insulated overhead line can be directly selected for use. A modern insulated overhead line is mainly made from cross-linked polyethylene and high-density polyethylene. For an exposed overhead line which has been erected in the past and still operates currently, insulation processing is also required, and will be replaced bit by bit with insulated overhead lines within the next few years. However, it will take a long time to remove an old exposed overhead line and reinstall a new insulated overhead line, and human and material resources invested in this process are costly, particularly in some remote, uneven areas with discrepancies between lines and houses, the cost of replacement with new lines is especially high.
Therefore, how to achieve the insulation processing in an existing exposed overhead line becomes an urgent problem to solve.